Cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute mortality and chronic disability in newborns, making the enormous physical and emotional strain that is placed on these individuals and their families a life long encumbrance. Despite the best efforts of the research community, an effective clinical therapy has yet to be established. Recently, erythropoietin (EPO) has been shown to be neuroprotective in both experimental and clinical studies. In a neonatal hypoxia-ischemia rat model, we have previously shown that the administration of exogenous recombinant human EPO (rhEPO) before and after the insult was able to preserve brain morphology and brain weight through an inhibition of apoptosis, possibly via an upregulation of HSP-27. Therefore, The objective of this proposal is to determine the mechanisms of neuroprotection by exogenous rhEPO treatment administered after a hypoxic-ischemic insult. The central hypothesis of this proposal is that exogenous rhEPO treatment will protect the brain against apoptosis, neuroinflammation, and the activition of matrix metalloproteinases (MMP). The rationale for the proposed research is that identifying the neuroprotective potential of rhEPO treatment and the mechanisms involved may provide a basis for extending the clinical application to infants suffering hypoxic- ischemic brain damage in the perinatal period. We will address three specific aims to test our central hypothesis. In Specific aim 1 we will examine the hypothesis that rhEPO will inhibit the apoptotic cascade via the upregulation of HSP70 and HSP27, thereby leading to a reduction in cell death, which translates into an improved neurological and behavioral outcome. In Specific aim 2, we will examine the hypothesis that rhEPO will decrease the neuroinflammatory response that follows the insult. In Specific aim 3, we will examine the hypothesis that rhEPO will induce the expression of tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2, which will decrease the activity of MMP-9 and MMP-2, respectively, thereby decreasing the disruption of the blood-brain barrier (BBB) and decreasing edema. An established neonatal hypoxia-ischemia model will be used in all these studies. We expect these proposed aims to demonstrate that rhEPO acts at multiple points in the pathological cascade of a hypoxic-ischemic insult and this combination of actions ultimately leads to the reduction of brain injury.